Suction-producing mechanism



C. C. BRAD BURY SUCTION PRODUCING MECHANISM March 18, 1930.

Filed May 17. 1920 r v I Patented Mar. 18, 1930 UNITED STATES PATEN'F OFFICE.

CLIFFORD C. BRADIBURY, OF OAK PARK, ILLINOIS, ASSIGNOR,.BY MESNE ASSIGN- MENTS, TO CURTIS B. CAMP, TRUSTEE, OAK PAR-K, ILLINOIS SUCTION-PRODUCING MECHANISM Application filed May 17, .1920. Serial No. 381,825.

This invention relates to suction producing mechanism for fuel lifting and other devices deriving their operating suction from the intake passages of internal combustion engines and particularly to a Venturi tube adapted to be automatically cut into and out of service to maintain suction sufficient at all times for lifting fuel from a low level main supply tank to a secondary supply tank at a higher level appurtenant to the carburetor of an internal combustion engine.

One of the objections to Vacuum fuel lifting systems for internal combustion engines is that while operating with wide open throttle at comparatively low speeds, the suction in the intake manifold of an engine drops to such a low value that it will not directly lift fuel through more than ten or fifteen inches.

This lowsuction occurs at the very time when the rear tank is at the greatest distance below the tank appurtenant to the carburetor because in ascending a hill, it is customary to operate an engine at its full power, that is,

with wide open throttle. At this time, the lift between the rear tank and the carburetor is much greater than when the vehicle is run tion in the engine manifold is high, the Venturi tube is drawn by the high suction to a position in which it ceases to operate as a Venturi tube and merely forms a part of a through connect-ionfrom the manifold to the suction pipe.

Whenever the manifold vacuum is low, a la-r e quantity of air is passing through the car uretor and into the engine so that the quantity of pure air which bleeds in through the Venturi tube does not materially disturb the mixture relation, and, therefore, does not detract from the power of the engine.

. however, this comparatively large bypass were permitted to remain when the throttle is wide open, the quantity of air drawn through the Venturi tube would be so great as to materially disturb the mixture proportions and therefore, it would interfere with the op eration of the engine. By reason of the automatic feature of this invention, the bypass is cut off whenever the suction is high enough that the fuel may be lifted directly without the boosting effect of the Venturi tube.

One feature of my invention resides in the construction enabling a purchaser to insert this vacuum boosting device in his present vacuum line. For that purpose, the device is made in the form of a plug having male and female ends for inclusion in existing lines. The device is preferably screwed directly into the engine manifold or carburetor, as the case may be, and the plug which was removed from the connection with the manifold or carburetor is then inserted in the protruding end of the device to complete the vacuum line.

The above and other features and advantages of my invention will appear from the following detailed description taken in conwherein Figure 1 is a side elevation of an internal combustion engine, and its appurtenant vacuum fuel feed-system, my improved vacuum boosting device being illustrated'as inserted in the vacuum line thereof.

Figure 2 is an enlarged longitudinal section of the device, the elements thereof being illustrated in the positions which they occupy when the suction in the intake manifold of the engine is comparatively small.

Figure 3 is a section taken on line 3-3 of Figure 2 looking in the direction indicated by the arrows, and v Figure 4 is a View similar to Figure 2, the elements of the device being illustrated in the positions which they occupy when the suction is high in the engine intake manifold.

The same reference numerals designate the same parts throughout the several views.

In Figure 1 of the drawings, a conventional internal combustion engine 5 is shown, hav- 9 ing the induction and exhaust manifolds 6 and 7 respectively. Bolted to the flange on the induction manifold 6 is a carburetor 8. Situated at a point above the level of the float chamber of the carburetor 8 is an auxiliary fuel feed tank 9. The tank 9 has communication with a low level main supply tank 10 through a pipe 11. A pipe 12 leads from the base of the tank 9 to the float chamber of the carburetor 8. Another pipe 13 establishes suction communication between the tank 9 and the induction manifold 6 of the engine 5 as shown; the vacuum boosting device of my invention, indicated generally by the reference numeral 14:, being inserted in the line between the end of the pipe 13 and the induction manifold 6 as aforesaid.

The operation of the vacuum fuel feed system shown being so well understood by engineers skilled in this art, it will not be necessary to go into any further detail in connection therewith. Although I have illustrated my invention as applied to a vacuum fuel feed system embodying an auxiliary fuel feed tank located at a point above the level of the carburetor, it will be distinctly understood that my invention is in no way limited to such use but may be used effectively in connection with systems of various types and forms as will hereinafter appear.

Referring now to Figures 2, 3 and 4 which are enlarged sectional details, it will be seen that the device 14E is in the form of a plug 15 having the threaded male and female ends 16 and 17 respectively, the male end 16 being threaded into the hole in the induction manifold 6 and the female end 17 being arranged to receive the end of the pipe 13 which conventionally is inserted in the hole in the induction manifold.

A bore 18 extends substantially the entire length of the plug 15 and is coaxial therewith. The bore 18 is reduced as at 19 to provide a shoulder 20. Seated upon the shoulder 20 is a compression spring 21 which tends to urge the slidable Venturi tube 22 normally upwardly away from the shoulder 20. A plug is threaded into the female end 17 and limits the upward movement of the Venturi tube 22. The Venturi tube 22 comprises a posterior end 2 1 and an anterior end 25, the

walls of the end 2 1 tapering gradually toward a throat 26 whence there is a sudden enlargement in the bore toward the end 25 as shown. Provided in the wall of the Venturi tube at the throat 26 is a plurality of radiating holes 2727 which communicate with an annular groove 28 provided in the outer wall of the Venturi tube. The groove 28 is comparatively broad and communicates, at all positions of the Venturi tube with a duct 29 extending vertically in the wall of the plug 15. At its upper end the duct 29 communicates with the inner end of the female portion 17 above the plug 23 as shown. It will, of course, be clear that the pipe 13 which threads into the end 17 will not extend into the plug 15 a sufiicient distance to cover the mouth of the duct 29. The groove 28 and hence the throat 26 of the Venturi tube are in constant communication with the pipe 13. A plug 30 closes the open anterior end 25 of the Venturi tube 22. A plurality of radiating holes 31 in the wall of the Venturi tube below the plug 30 establishes communication between the anterior end 25 of the Venturi tube and an annular groove 32 provided in the outer wall of the Vcnturi tube 22. An opening 33 in the wall of the plug 15 establishes communication between the anterior end 25 of the Venturi tube and the atmosphere when the Venturi tube is in the position illustrated in Figure 2; this communication being broken when the Venturi tube moves inwardly to the position shown in Figure 4, at which position the suction in the induction manifold 6 of the engine is comparatively high.

The operation of the device is as follows:

Assume that the engine 5 is operating at low speeds with wide open throttle at which time the vacuum produced in the intake manifold 6 is consequently small or more specifically assume that we are ascending a hill with wide open throttle at which time the main supply tank 10 is at its lowest level relative to the secondary supply tank 9 and the carburetor 8.

The suction produced in the manifold 6 is communicated to the posterior end 24 of the Venturi tube 22 through the bores 19 and 18. The suction produced at the throat 26 is greater than the suction produced at the posterior end 2 1. This increased suction is communicated to the auxiliary supply tank 9 through the holes 27 groove 28, duct 29 and pipe 13. The lift of fuel is, therefore, considerably increased over that formerly possible. In fact, I have found that the suction produced in the tank 9 is sufficient for lifting fuel under all engine operating conditions.

When the engine is operating under the slow-speed wide-open throttle condition, as above indicated, air is drawn into the intake through the openings 33 and 31, but inasmuch as the quantity of this air is very small as compared with the amount of mixture at that time being drawn through the intake manifold, the mixture will not be unduly disturbed. It is possible to adjust the carburetor so that whenever the engine is operated under the conditions above named, the mix ture would be unduly rich excepting for this additional quantity of air which is drawn in through the Venturi tube 22. When the engine is being operated with nearly closed throttle, the suction in the manifold is very high and if the openings 31 were not closed off, the quantity of air which would then be drawn through the Venturi tube 22 would disturb the mixture to such an extent that it would be non-explosive. The Venturi tube 22 is arranged under such conditions to move inwardly to the position illustrated in Figure 4 against the tension of the spring 21.

The difference in pressure existing between the posterior end and the anterior end of the Venturi tube, under such conditions, causes the same to move inwardly. As seen in Figure 4, the communication between the anterior end of the Venturi tube 22 and the atmosphere through the openings 31 and the opening 33 is broken when the Venturi tube moves into this position. The suction produced in the induction manifold 6 is communicated directly to the tank 9 through the bores 19 and 21, the holes 27, duct 29 and pipe 13, the Venturi tube 22, under such conditions, forming merely a part of a through connection from the manifold to the pipe 13.

In the above description, I have described the device 14 as operating in a vertical position and have correspondingly referred to upper and lower portions thereof. It must be understood that the device is as readily operable when placed in any position, it being necessary merely to adjust properly, the tension of the spring 21.

While I have described the details of a preferred embodiment of my invention, I do not limit myself to the details shown, but claim all equivalent embodiments coming within the spirit and scope of the appended claims.

What I claim is 1. In a fuel feeding system, a device for amplifying the suction for lifting fuel from a low level reservoir to a position above the level of the carburetor of an engine, said device comprising a plug in the suction line of said system having a bore extending therethrough. a slidably mounted Venturi tube in said bore, the posterior end of said Venturi tube being subject to said suction, and the anterior end thereof being subject to atmosphere, and a spring for normally holding said.

Venturi tube in a position for amplifying said suction and when said suction attains a predetermined value, to permit the movement of said Venturi tube against the pressure of said spring, and means to cut off the communication between the anterior end of said Venturi tube and atmosphere to render said Venturi tube inoperative as an amplifier when the tube is so moved.

2. In a fuel feeding system a device for amplifying the suction for lifting fuel from a low level reservoir above the level of the carburetor of an engine, said device comprising a plug in the suction line of said system, a bore extending therethrough, a Venturi tube in said bore, the posterior end of said Venturi tube being subject to said suction, and the anterior end thereof being subject to atmosphere, and means for holding said Venturi tube in a position for amplifying said suction, said Venturi tube being movable against said means by said suction, to cut off the communication between the anterior end of said Venturi tube and atmosphere to render said Venturi tube inoperative as an amplifier.

3. A device for amplifying the suction obtained from the intake manifold of an internal combustion engine, comprising a cylindrical container, a Venturi tube reciprocable in said container, a connection between one end of said container and the engine manifold, a connection between the other end of said container and the apparatus to receive the amplified suction, said container having atmospheric openings therein normally connecting with the anterior end of said Venturi tube, a connection between the throat of said Venturi tube and the amplified suction line and means associated with said Venturi tube for cutting off the atmospheric connection with its anterior end when the suction in the manifold reaches a predetermined value.

In witness whereof, I hereunto subscribe my name this 14th day of May, 1920.

CLIFFORD C. BRADBURY. 

